Flavour-wise, I kind of like astral combat being its own thing. It emphasizes the strange nature of a combat where movement is so fast, damage is done by willing it as much as anything else, etc.
Mechanically, I find it really intriguing. It would literally make a couple of character builds that I'd given up on suddenly work, it would give some mages some back up combat skills (when really they wanted astral combat) and others some back up astral combat (when really they wanted melee skills). Hobbes is right, though, that in general mages are doing just fine.